TRIGGER WARNING: if you are uncomfortable discussing bowel function, including some fairly graphic descriptions, stop reading this now, curl into a fetal ball and rock back and forth on the floor.

I’ve been meaning to respond to the discussion regarding overactive bowels during running which was “stimulated” by my post regarding fueling for long-distance racing.

As Corey pointed out, I am actually an expert on this issue in more ways than one. I tend to be “regular” and even more “regular” when I run. In fact, part of the reason I avoid running in the mornings is that I inevitably have to stop in the woods somewhere, or circle home, or pretend I’m a guest at a downtown hotel as I stride purposefully towards their lobby bathroom. This is not new for me. I’m built that way. I was known for that when I first started running as a lanky awkward teenager back in the mid-80’s (now I’m a lanky awkward old guy).

In fact, I am honored/totally embarrassed to say that the act of stopping mid-workout or mid-race, particularly in an inappropriate place (often outdoors, and far too public) to relieve oneself has actually been named “doing a Bighead”. As in “I was heading for a PB but I had to stop and do a Bighead in someone’s hedge”

But in my own defense, this is actually a very common complaint/issue. Common enough that it has a nickname: “runners’ trots”.

I could regale you all with many stories of the places I’ve had to stop, the races that have been sabotaged by my colon (it’s the reason I don’t have a set of swordfish swords from Louisbourg), the times I’ve missed the starting gun siting in a port-a-john, and the many times I’ve embarrassed myself. But I’ll skip that and just go on to the science.

I glossed over a lot of the details of how the GI system reacts to exercise in my post about fueling. It is true that the stomach shuts down. A phenomenon called “gastric motility” (the coordinated squeezing movements of the stomach and esophagus that move stuff through and down to the small bowel) greatly decrease, which is why people get heartburn and nausea when they try to eat while exercising (especially running, which is probably worse because of jostling and increased pressure inside the abdomen). But the upper GI system is just half of the story.

The lower bowel’s (initial) reaction to exercise is to try to empty out. In fact, for many of us, even the expectation of running will cause a “colonic reaction” where your colon contracts and peristalses (those coordinated movements again) to try to empty.

This is probably an evolutionary adaptation. Gorilla troops, when agitated and getting ready to travel, will generally all go and move their bowels before they leave. Makes sense. Trying to hoof it for a few hours with a big load of dump in one’s bowel is pretty inefficient, and probably slows you down.

There are definitely a few pointers I would share for dealing with this issue, refined after 30-plus years of practice:

1) when racing, especially an “A-race”, think about what you eat the night before. A really spicy curry veggie dish with tons of fibre, perhaps not the best option.

2) Avoid eating any solids for about 3 hours before, and any liquids for about an hour. There is something called the “gastro-colic reflex” where putting things in the stomach stimulates the lower bowel to empty.

3) Make sure to BM before leaving for a run! Even if you don’t really “have to”.

4) If you habitually have to go during runs, pick routes that have bathrooms (or at least woods), and carry toilet paper. I know every patch of woods and every public bathroom within a 10 mile radius of my place. Plus my friends and relatives know what’s up when I frantically beat on their door, all sweaty and dressed in my running gear.

5) Experiment with running at different time of day (if you have that luxury). I know a few people besides myself who just can’t get the hang of running in the morning without having morning runs. Listen to your body. Later day is often better.

6) Experiment with different foods before key workouts and races. Find what works for you. Oddly, if your fibre intake is too low, more fibre can actually “bulk” your stool and make it less watery, which can actually help avoid the runners’ trots.

Embrace it! The bowel regularity that comes with physical activity may be part of the reason that active folks are less prone to bowel cancer. And talk to any chronically constipated person. They would trade places with you anytime.